Automated systems for moving containers within a warehouse represent an opportunity to provide advantages in container handling, including providing increased speed of movement, more accurate tracking of product and reduced cost, particularly for medium to large sized warehouses. The automated system may be in the form of one or more conveyors and/or a robot movable over a working area.
The amount of useful work that a robot system performs is dependent on the speed of travel of the robot and the distance that the robot has to travel between each pick-up and drop-off of containers. If a distance greater than the minimum required distance is travelled by a robot, there is a corresponding reduction in the throughput capacity of the warehouse.
A robot system is described in the specification published as European Patent Publication EP0767113. The system includes a robot that travels over a horizontal pick face formed by a number of stacks of containers. The robot has a vertically movable gripping device that is lowered over a stack until a required number of containers are enclosed within an enclosed loading space. The gripping device then grips the containers, raises them above the pick face and transports them to a required location, where they are lowered onto the ground or onto a partial stack of containers. The amount of travelling that the robot has to do is dependent on the spacing of the pick-up and drop-off points and the vertical distance that the robot has to travel to pick-up and drop off stacks. The vertical movement required to enclose the gripped containers can materially increase the time needed to pick-up and drop off stacks. The robot requires a large amount of space above the stacks, at least one stack high in order to be able to move over the stacks. This can be disadvantageous in some implementations where vertical space is limited. Raising a heavy gripper and heavy contained load into the space above the stored stacks and moving them quickly through this space requires a substantial robot together with substantial supporting structure. Such a robot and support structure is expensive to manufacture, install and commission.
Other automated picking systems include what is known as an Automated Storage and Retrieval System (ASRS). An example ASRS is described in the specification of U.S. Pat. No. 5,379,229. An ASRS uses racks to store containers, and is thus not suitable for use with individual stacks of containers placed one on top of each other on a store surface. Thus, an ASRS may be unsuitable for low volume retrieval of containers.
It is thus an object of the present invention to provide apparatus for moving containers within a warehouse that overcome or alleviate problems in such at present.
Another or alternative object of one embodiment of the present invention is to provide apparatus for moving containers that is viable for low volume container picking or to provide apparatus for moving containers within a warehouse that has less vertical space available.
Another or alternative object of one embodiment of the present invention is to provide apparatus for moving containers that is of less cost, shorter installation period and/or requiring less substantial supporting structure than existing apparatus at present.
Another or alternative object of the present invention is to at least provide the public with a useful alternative
Further objects of the present invention may become apparent from the following description.